drm/i915/error: capture uc_state after gen_state

drm/i915/error: capture uc_state after gen_state

error->device_info.has_guc, which we check in capture_uc_state, is set
in capture_gen_state, so the latter needs to be performed first.

v2: rebased

Reported-by: Vinay Belgaumkar <vinay.belgaumkar@intel.com>
Fixes: 7d41ef3479a6 (drm/i915: Add Guc/HuC firmware details to error state)
Cc: Vinay Belgaumkar <vinay.belgaumkar@intel.com>
Cc: Michal Wajdeczko <michal.wajdeczko@intel.com>
Cc: Chris Wilson <chris@chris-wilson.co.uk>
Signed-off-by: Daniele Ceraolo Spurio <daniele.ceraolospurio@intel.com>
Reviewed-by: Chris Wilson <chris@chris-wilson.co.uk>
Link: https://patchwork.freedesktop.org/patch/msgid/20180305222122.3547-3-daniele.ceraolospurio@intel.com
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>